* [Bug 1926231] [NEW] SCSI passthrough of SATA cdrom -> errors & performance issues
@ 2021-04-27 0:39 Michael Slade
2021-04-27 13:34 ` [Bug 1926231] " Michael Slade
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Michael Slade @ 2021-04-27 0:39 UTC (permalink / raw)
To: qemu-devel
Public bug reported:
qemu 5.0, compiled from git
I am passing through a SATA cdrom via SCSI passthrough, with this
libvirt XML:
<hostdev mode='subsystem' type='scsi' managed='no' sgio='unfiltered' rawio='yes'>
<source>
<adapter name='scsi_host3'/>
<address bus='0' target='0' unit='0'/>
</source>
<alias name='hostdev0'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</hostdev>
It seems to mostly work, I have written discs with it, except I am
getting errors that cause reads to take about 5x as long as they should,
under certain circumstances. It appears to be based on the guest's read
block size.
I found that if on the guest I run, say `dd if=$some_large_file
bs=262144|pv > /dev/null`, `iostat` and `pv` disagree about how much is
being read by a factor of about 2. Also many kernel messages like this
happen on the guest:
[ 190.919684] sr 0:0:0:0: [sr0] tag#160 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE cmd_age=0s
[ 190.919687] sr 0:0:0:0: [sr0] tag#160 Sense Key : Aborted Command [current]
[ 190.919689] sr 0:0:0:0: [sr0] tag#160 Add. Sense: I/O process terminated
[ 190.919691] sr 0:0:0:0: [sr0] tag#160 CDB: Read(10) 28 00 00 18 a5 5a 00 00 80 00
[ 190.919694] blk_update_request: I/O error, dev sr0, sector 6460776 op 0x0:(READ) flags 0x80700 phys_seg 5 prio class 0
If I change to bs=131072 the errors stop and performance is normal.
(262144 happens to be the block size ultimately used by md5sum, which is
how I got here)
I also ran strace on the qemu process while it was happening, and
noticed SG_IO calls like this:
21748 10:06:29.330910 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x95\x5a\x00\x00\x80\x00", mx_sb_len=252, iovec_count=0, dxfer_len=262144, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21751 10:06:29.330976 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xda\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21749 10:06:29.331586 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xdc\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
[etc]
I suspect qemu is the culprit because I have tried a 4.19 guest kernel
as well as a 5.9 one, with the same result.
** Affects: qemu
Importance: Undecided
Status: New
--
You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1926231
Title:
SCSI passthrough of SATA cdrom -> errors & performance issues
Status in QEMU:
New
Bug description:
qemu 5.0, compiled from git
I am passing through a SATA cdrom via SCSI passthrough, with this
libvirt XML:
<hostdev mode='subsystem' type='scsi' managed='no' sgio='unfiltered' rawio='yes'>
<source>
<adapter name='scsi_host3'/>
<address bus='0' target='0' unit='0'/>
</source>
<alias name='hostdev0'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</hostdev>
It seems to mostly work, I have written discs with it, except I am
getting errors that cause reads to take about 5x as long as they
should, under certain circumstances. It appears to be based on the
guest's read block size.
I found that if on the guest I run, say `dd if=$some_large_file
bs=262144|pv > /dev/null`, `iostat` and `pv` disagree about how much
is being read by a factor of about 2. Also many kernel messages like
this happen on the guest:
[ 190.919684] sr 0:0:0:0: [sr0] tag#160 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE cmd_age=0s
[ 190.919687] sr 0:0:0:0: [sr0] tag#160 Sense Key : Aborted Command [current]
[ 190.919689] sr 0:0:0:0: [sr0] tag#160 Add. Sense: I/O process terminated
[ 190.919691] sr 0:0:0:0: [sr0] tag#160 CDB: Read(10) 28 00 00 18 a5 5a 00 00 80 00
[ 190.919694] blk_update_request: I/O error, dev sr0, sector 6460776 op 0x0:(READ) flags 0x80700 phys_seg 5 prio class 0
If I change to bs=131072 the errors stop and performance is normal.
(262144 happens to be the block size ultimately used by md5sum, which
is how I got here)
I also ran strace on the qemu process while it was happening, and
noticed SG_IO calls like this:
21748 10:06:29.330910 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x95\x5a\x00\x00\x80\x00", mx_sb_len=252, iovec_count=0, dxfer_len=262144, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21751 10:06:29.330976 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xda\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21749 10:06:29.331586 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xdc\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
[etc]
I suspect qemu is the culprit because I have tried a 4.19 guest kernel
as well as a 5.9 one, with the same result.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1926231/+subscriptions
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug 1926231] Re: SCSI passthrough of SATA cdrom -> errors & performance issues
2021-04-27 0:39 [Bug 1926231] [NEW] SCSI passthrough of SATA cdrom -> errors & performance issues Michael Slade
@ 2021-04-27 13:34 ` Michael Slade
2021-05-15 11:17 ` Thomas Huth
2021-07-15 4:17 ` Launchpad Bug Tracker
2 siblings, 0 replies; 4+ messages in thread
From: Michael Slade @ 2021-04-27 13:34 UTC (permalink / raw)
To: qemu-devel
Just discovered that `hdparm -a 128` works around the issue (it was 256
at boot).
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1926231
Title:
SCSI passthrough of SATA cdrom -> errors & performance issues
Status in QEMU:
New
Bug description:
qemu 5.0, compiled from git
I am passing through a SATA cdrom via SCSI passthrough, with this
libvirt XML:
<hostdev mode='subsystem' type='scsi' managed='no' sgio='unfiltered' rawio='yes'>
<source>
<adapter name='scsi_host3'/>
<address bus='0' target='0' unit='0'/>
</source>
<alias name='hostdev0'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</hostdev>
It seems to mostly work, I have written discs with it, except I am
getting errors that cause reads to take about 5x as long as they
should, under certain circumstances. It appears to be based on the
guest's read block size.
I found that if on the guest I run, say `dd if=$some_large_file
bs=262144|pv > /dev/null`, `iostat` and `pv` disagree about how much
is being read by a factor of about 2. Also many kernel messages like
this happen on the guest:
[ 190.919684] sr 0:0:0:0: [sr0] tag#160 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE cmd_age=0s
[ 190.919687] sr 0:0:0:0: [sr0] tag#160 Sense Key : Aborted Command [current]
[ 190.919689] sr 0:0:0:0: [sr0] tag#160 Add. Sense: I/O process terminated
[ 190.919691] sr 0:0:0:0: [sr0] tag#160 CDB: Read(10) 28 00 00 18 a5 5a 00 00 80 00
[ 190.919694] blk_update_request: I/O error, dev sr0, sector 6460776 op 0x0:(READ) flags 0x80700 phys_seg 5 prio class 0
If I change to bs=131072 the errors stop and performance is normal.
(262144 happens to be the block size ultimately used by md5sum, which
is how I got here)
I also ran strace on the qemu process while it was happening, and
noticed SG_IO calls like this:
21748 10:06:29.330910 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x95\x5a\x00\x00\x80\x00", mx_sb_len=252, iovec_count=0, dxfer_len=262144, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21751 10:06:29.330976 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xda\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21749 10:06:29.331586 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xdc\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
[etc]
I suspect qemu is the culprit because I have tried a 4.19 guest kernel
as well as a 5.9 one, with the same result.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1926231/+subscriptions
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug 1926231] Re: SCSI passthrough of SATA cdrom -> errors & performance issues
2021-04-27 0:39 [Bug 1926231] [NEW] SCSI passthrough of SATA cdrom -> errors & performance issues Michael Slade
2021-04-27 13:34 ` [Bug 1926231] " Michael Slade
@ 2021-05-15 11:17 ` Thomas Huth
2021-07-15 4:17 ` Launchpad Bug Tracker
2 siblings, 0 replies; 4+ messages in thread
From: Thomas Huth @ 2021-05-15 11:17 UTC (permalink / raw)
To: qemu-devel
The QEMU project is currently moving its bug tracking to another system.
For this we need to know which bugs are still valid and which could be
closed already. Thus we are setting the bug state to "Incomplete" now.
If the bug has already been fixed in the latest upstream version of QEMU,
then please close this ticket as "Fix released".
If it is not fixed yet and you think that this bug report here is still
valid, then you have two options:
1) If you already have an account on gitlab.com, please open a new ticket
for this problem in our new tracker here:
https://gitlab.com/qemu-project/qemu/-/issues
and then close this ticket here on Launchpad (or let it expire auto-
matically after 60 days). Please mention the URL of this bug ticket on
Launchpad in the new ticket on GitLab.
2) If you don't have an account on gitlab.com and don't intend to get
one, but still would like to keep this ticket opened, then please switch
the state back to "New" or "Confirmed" within the next 60 days (other-
wise it will get closed as "Expired"). We will then eventually migrate
the ticket automatically to the new system (but you won't be the reporter
of the bug in the new system and thus you won't get notified on changes
anymore).
Thank you and sorry for the inconvenience.
** Changed in: qemu
Status: New => Incomplete
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1926231
Title:
SCSI passthrough of SATA cdrom -> errors & performance issues
Status in QEMU:
Incomplete
Bug description:
qemu 5.0, compiled from git
I am passing through a SATA cdrom via SCSI passthrough, with this
libvirt XML:
<hostdev mode='subsystem' type='scsi' managed='no' sgio='unfiltered' rawio='yes'>
<source>
<adapter name='scsi_host3'/>
<address bus='0' target='0' unit='0'/>
</source>
<alias name='hostdev0'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</hostdev>
It seems to mostly work, I have written discs with it, except I am
getting errors that cause reads to take about 5x as long as they
should, under certain circumstances. It appears to be based on the
guest's read block size.
I found that if on the guest I run, say `dd if=$some_large_file
bs=262144|pv > /dev/null`, `iostat` and `pv` disagree about how much
is being read by a factor of about 2. Also many kernel messages like
this happen on the guest:
[ 190.919684] sr 0:0:0:0: [sr0] tag#160 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE cmd_age=0s
[ 190.919687] sr 0:0:0:0: [sr0] tag#160 Sense Key : Aborted Command [current]
[ 190.919689] sr 0:0:0:0: [sr0] tag#160 Add. Sense: I/O process terminated
[ 190.919691] sr 0:0:0:0: [sr0] tag#160 CDB: Read(10) 28 00 00 18 a5 5a 00 00 80 00
[ 190.919694] blk_update_request: I/O error, dev sr0, sector 6460776 op 0x0:(READ) flags 0x80700 phys_seg 5 prio class 0
If I change to bs=131072 the errors stop and performance is normal.
(262144 happens to be the block size ultimately used by md5sum, which
is how I got here)
I also ran strace on the qemu process while it was happening, and
noticed SG_IO calls like this:
21748 10:06:29.330910 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x95\x5a\x00\x00\x80\x00", mx_sb_len=252, iovec_count=0, dxfer_len=262144, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21751 10:06:29.330976 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xda\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21749 10:06:29.331586 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xdc\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
[etc]
I suspect qemu is the culprit because I have tried a 4.19 guest kernel
as well as a 5.9 one, with the same result.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1926231/+subscriptions
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug 1926231] Re: SCSI passthrough of SATA cdrom -> errors & performance issues
2021-04-27 0:39 [Bug 1926231] [NEW] SCSI passthrough of SATA cdrom -> errors & performance issues Michael Slade
2021-04-27 13:34 ` [Bug 1926231] " Michael Slade
2021-05-15 11:17 ` Thomas Huth
@ 2021-07-15 4:17 ` Launchpad Bug Tracker
2 siblings, 0 replies; 4+ messages in thread
From: Launchpad Bug Tracker @ 2021-07-15 4:17 UTC (permalink / raw)
To: qemu-devel
[Expired for QEMU because there has been no activity for 60 days.]
** Changed in: qemu
Status: Incomplete => Expired
--
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1926231
Title:
SCSI passthrough of SATA cdrom -> errors & performance issues
Status in QEMU:
Expired
Bug description:
qemu 5.0, compiled from git
I am passing through a SATA cdrom via SCSI passthrough, with this
libvirt XML:
<hostdev mode='subsystem' type='scsi' managed='no' sgio='unfiltered' rawio='yes'>
<source>
<adapter name='scsi_host3'/>
<address bus='0' target='0' unit='0'/>
</source>
<alias name='hostdev0'/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</hostdev>
It seems to mostly work, I have written discs with it, except I am
getting errors that cause reads to take about 5x as long as they
should, under certain circumstances. It appears to be based on the
guest's read block size.
I found that if on the guest I run, say `dd if=$some_large_file
bs=262144|pv > /dev/null`, `iostat` and `pv` disagree about how much
is being read by a factor of about 2. Also many kernel messages like
this happen on the guest:
[ 190.919684] sr 0:0:0:0: [sr0] tag#160 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE cmd_age=0s
[ 190.919687] sr 0:0:0:0: [sr0] tag#160 Sense Key : Aborted Command [current]
[ 190.919689] sr 0:0:0:0: [sr0] tag#160 Add. Sense: I/O process terminated
[ 190.919691] sr 0:0:0:0: [sr0] tag#160 CDB: Read(10) 28 00 00 18 a5 5a 00 00 80 00
[ 190.919694] blk_update_request: I/O error, dev sr0, sector 6460776 op 0x0:(READ) flags 0x80700 phys_seg 5 prio class 0
If I change to bs=131072 the errors stop and performance is normal.
(262144 happens to be the block size ultimately used by md5sum, which
is how I got here)
I also ran strace on the qemu process while it was happening, and
noticed SG_IO calls like this:
21748 10:06:29.330910 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x95\x5a\x00\x00\x80\x00", mx_sb_len=252, iovec_count=0, dxfer_len=262144, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21751 10:06:29.330976 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xda\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
21749 10:06:29.331586 ioctl(22, SG_IO, {interface_id='S', dxfer_direction=SG_DXFER_FROM_DEV, cmd_len=10, cmdp="\x28\x00\x00\x12\x94\xdc\x00\x00\x02\x00", mx_sb_len=252, iovec_count=0, dxfer_len=4096, timeout=4294967295, flags=SG_FLAG_DIRECT_IO <unfinished ...>
[etc]
I suspect qemu is the culprit because I have tried a 4.19 guest kernel
as well as a 5.9 one, with the same result.
To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1926231/+subscriptions
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-07-15 4:29 UTC | newest]
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2021-04-27 0:39 [Bug 1926231] [NEW] SCSI passthrough of SATA cdrom -> errors & performance issues Michael Slade
2021-04-27 13:34 ` [Bug 1926231] " Michael Slade
2021-05-15 11:17 ` Thomas Huth
2021-07-15 4:17 ` Launchpad Bug Tracker
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